In our modern day society, good posture is becoming more and more essential to the integrity or our health and well-being. Most of our jobs and transportation involve a seated position for hours at a time. Even the exercise equipment in the gym involves sitting! According to the research of Nachemson, this is the worst position for our spine. In fact, Nachemson estimates 30 -40% more stress on the disc when in a seated position. (1) This doesn’t mean we shouldn’t sit down, but does, however, indicate we should be very conscious of good posture while we sit or exercise while in a seated position. It also makes you wonder about the exercises being promoted. We sit while traveling to and from work where we sit again, and then off to the gym to sit some more. Sitting or existing in poor postural alignment can eventually cause a host of health problems. Posture is becoming such a “buzz word” that people are promoting themselves as “Occupational Postural Engineers,” “Posture Experts,” or “Ergonomical Postural Analysts.” After reading this article you will have a better understanding of what ideal posture is, how to identify faulty posture and what can be done about it.
First we need to learn some terms.
Posture: The position of the limbs or the carriage of the body as a whole. Stedman’s Medical Dictionary
Posture: The relative arrangement of the parts of the body. Good posture is that state of muscular and skeletal balance which protects the supporting structures of the body against injury or progressive deformity irrespective of the attitude (erect, lying, squatting, stooping, sitting) in which these structures are working or resting. Muscles Testing and Function, fourth Edition
Postural Control: A person’s ability to maintain stability of the body or body segments in response to forces that threaten to disturb the body’ structural equilibrium.
Facilitation: Enhancement or reinforcement of a reflex or other nervous activity by the arrival of other nervous activity at the reflex center of other excitatory impulses.Stedman’s Medical Dictionary
Inhibition: A nerve, stimulation of which represses activity. Stedman’s Medical Dictionary
Posture can be static or dynamic. Sitting, standing or lying are examples of static posture while running, jumping, throwing, walking and lifting or examples of dynamic posture.
Static posture is the basis for understanding dynamic posture, therefore the first place to start is the static position. Be careful, a posture may appear to be very faulty, yet the individual may be flexible and the position of the body may change readily. A posture may also appear to be good, but the stiffness or muscle tightness that is present may limit mobility that position may not change readily.
Postural control which can either be static or dynamic, refers to ability to maintain stability of the body and body segments in response to forces that threaten to disturb the body’s structural equilibrium.
Maintenance and/or control of posture depends on the integrity of the central nervous system (CNS), the visual system, the vestibular system, the musculo-skeletal system and inputs from receptors located in and around the joints and in tendons and ligaments.(2) A person’s ability to maintain erect posture may be affected by the inability of the muscles to respond appropriately to signals from the CNS. For example, in the elderly, the muscle’s response time to the signal may be decreased in comparison to a younger individual.
It is important to understand the imbalances that can occur with faulty posture. By stretching and lengthening the muscles that are short and tight (facilitated) and strengthening the muscles that are long and weak (inhibited), you will be able to move more efficiently in everyday life. In some instances, good posture or improving one’s posture may even cure or prevent pain from muscle spasms, trigger points, nerve entrapments, muscle strains, sprains, respiratory challenges or even vascular problems. In essence, good posture is king!
When looking at someone’s posture it’s best to look from the front, back and then from each side. Some postural experts start at the head, but I like to start at the feet. Stand stark naked or with as little clothes as possible and face a full length mirror. Take a good look at yourself. Don’t stand at attention. Relax, stand normal. When assessing someone else’s posture, don’t tell them what you’re looking for otherwise they won’t stand normal.
Your feet should be pointing straight ahead. Your big toe or first ray should point straight ahead as well. The toe should not deviate outward. A person should be able to fit the thickness of their thumb under the arch of your foot. The ankle should not “bow” in, nor outward and stand vertical so there is a right angle to the sole of the foot. The knees should point straight over the big toe and the second toe. They should not “squint” inwards nor “bow” outward. The knees shouldn’t be bent (flexed) not bent backwards (hyper- extended). The pelvis should be level on either side. You may palpate your ASIS (anterior superior iliac spine) with your fingers or lie your hands on the top of the ilium to see if they’re level (see picture) The hip should also be in neutral, neither flexed (bent forward) or extended (bent backwards).The hands should be of equal length, palms facing inward towards the thigh. They should not be too far in front of the body.
There should be equal distance between the inside of the elbow and the torso on either side of the body. Always match one side of the body to the other for symmetry. The shoulders should be level and the head should sit right in the middle. This is ideal posture from the front.
You won’t be able to assess your own posture from the side nor the back unless someone takes a picture. From the back, your heel chord or Achilles tendon should be straight. It shouldn’t “bow” inward or outward. The ankle should be right under the tibia and fibula. The knees should be of the same height. At the pelvis you can now palpitate the PSIS (posterior superior iliac spine). These little “knobs” should be level. The elbows should not “flair” outward nor inward. The shoulder blades or scapulae should be of equal distance from the spine and should not wing or tip outward or upward. Look for symmetry of the musculature in the spinal erectors. Again, the shoulders should be level with the head set right in the middle of the body.
From the side, imagine a plumb line running through the middle of the ankle, knee, hip, shoulder and the ear. The ankle is vertical at a right angle to the foot, the knee and the hip are neither flexed or extended, the PSIS is slightly higher than the ASIS (the difference is about ½ inch in males and 3/4 inch in females) and the shoulder and head are not rounded nor tilted forward or backward. The spine is in neutral with the lumbar and cervical spine curved slightly convex anteriorly (towards the front or calledlordosis), the sacrum and the thoracic spine slightly convex posteriorly (towards the back or kyphosis).
Head: Neutral position, not tilted forward or backward. From the lateral side, ear should be level with the shoulder.
Cervical Spine: Normal curve. Slightly convex towards the front of the body (anteriorly). Scapulae: Flat against upper back.
Thoracic Spine: Normal curve, slightly convex to the back of the body (posteriorly). Lumbar Spine: Normal curve, towards the front of the body (anteriorly).
Pelvis: Neutral position, ASIS in the same vertical plane as the pubic symphysis. ASIS should be lower than the PSIS by ½ inch in males or 3/4 inch in females.
Hip Joints: Neutral position, neither flexed or extended
Knee Joints: Neutral position, neither flexed nor hyper-extended.
Ankle Joints: Neutral position, leg vertical and at a right angle to the leg.(3)
KYPHOSIS – LORDOSIS POSTURE
This is also referred to as Upper Cross and Lower Cross Syndrome.(4) Before I go into this further you must understand the concept of muscles being “facilitated” or “inhibited.” Hence a little muscle physiology is in order.
For your muscles to contract or shorten they must first receive a signal or an “action potential” from a nerve. The nerve and the muscle fibers it inervates is called a motor unit. Some motor units are larger than others. A larger motor unit will need a larger “spike” or action potential to inervate all the muscle fibers attached to that particular unit. The size or type of muscle fiber is also a factor. Fast-twitch fibers are larger than slow-twitch fibers hence a larger motor neuron with a larger action potential is required to make the muscle shorten. All muscles in your body contain a mixture of these muscle fiber types but, it turns out,
postural muscles contain a greater percentage of slow-twitch fibers. Slow-twitch fibers are fatigue resistant, contain a smaller motor neuron, are recruited first and are primarily aerobic in nature.
Therefore, postural muscles are easily facilitated, which means they have a tendency to shorten and become tight. A good example would be the upper trapezius.(5) In the faulty posture above, you’ll notice the head is in front of the plumb line. Since a person’s head can weigh approximately 8% of their body weight, this could be a considerable weight to hold out all day. (6) The upper trapezius along with other muscles must hold the head out in space for long periods of time. Physiologists, Physical Therapists and Personal Trainers refer to these types of muscles as tonic muscles because they’re usually always “on.” Tonic muscles are primarily slow-twitch, contain small motor units, lie deep inside the body, are postural and are easily facilitated (short and tight). In contrast, the phasic muscles are made up of predominantly fast-twitch muscle fibers, are more superficial, have a larger motor neuron, have a tendency to become long and weak and are sometimes “on” or “off.” For instance, while sitting reading this article your bicep is probably “off.” Lift the magazine with that arm and that bicep will turn “on.” With these concepts in mind, let’s examine the posture above. It is easier to spot this type of posture from the side.
The feet will have a slight angle downward from the leg (slight plantar flexion) because of the backward inclination of the leg. The knee joints may be slightly hyper-extended. The pelvis is tilted forward (anterior) while the lumbar, thoracic and cervical spine have exaggerated curvatures. The scapulae are abducted or have moved forward on the torso (thorax) and the head is held forward in front of the body. This posture creates an imbalance between the musculature in the front and back of the body. (Picture)
Muscles short and facilitated: Neck extensors, (the muscle in the back of the neck), upper trapezius, sternocleidomastoid, pectoralis major and minor, lumbar erector spinae, hip flexors, tensor fascia latae, rectus femoris and gastrocnemius.
Elongated and Inhibited: Deep neck flexors, (the muscles in front of the neck), lower, middle trapezius, rhomboids, serratus anterior, rectus abdominis, gluteus maximus, gluteus medius, vasti group and the anterior tibialis. (7)
The first thing to address is the tight musculature. Stretch the tight facilitated muscles first. Because of Sherrington’s Law of Reciprocal Inhibition, the short facilitated muscles will inhibit or deactivate the antagonist muscles. For example, tight hip flexors will inhibit the Gluteus Maximus (your butt).(8) By stretching the tight muscles beforeexercising the inhibited muscles, EMG studies show the inhibited muscles receiving more neural input.(9) If you’re unclear on how to stretch a muscle, look in an anatomy book that shows the origin and insertion of the muscle you want to stretch. Once you see where the muscle attaches at both ends, just stretch the two ends away from each other. Be careful not to exceed normal range of motion though. You don’t want to end up with a hyper-mobile joint. Be careful not to stretch all the muscles. Just stretch the tight ones. If you stretch the muscles that are already elongated
and weak you could interfere with the normal firing pattern. (10) Once you’ve stretched what’s tight, you can now exercise the inhibited musculature based on the goal. Remember, slow-twitch respond better to light weights and high repetitions.
Cervical Spine: Hyper-extended
Scapulae: Abducted (rounded around the thorax). Thoracic Spine: Increased flexion, (kyphosis).
Lumbar Spine: Hyper-extended, (lordosis).
Pelvis: Anterior tilt. The pelvis or ASIS is tilted forward. Hip Joints: Flexed
Knee Joints: Slightly hyper-extended.
Ankle Joints: Slight tilt forward (plantar flexion) (11)
FLAT-BACK POSTURE (picture)
This posture is common in shy people and women who often wear high heels. Because the center of gravity has been thrown forward many women tend to tilt their pelvis backwards and kind of “hang” on their ligaments. From the side, the head is in front of the plumb line, the cervical spine is slightly extended, while the thoracic spine is exaggerated slightly. The lower back (lumbar) is straight or flexed while the pelvis is tilted backwards (posterior).
Muscles short and facilitated: Hamstrings, abdominals.
Elongated and Inhibited: One joint hip flexors. (12)
Again, this is purely anecdotal on my part. Stretch the hamstrings and the abdominals.
Strengthen the hip flexors. At first glance it might appear the muscles of the lower back would be long and weak. Check for strength of the lumbar erectors. See if you can hold yourself horizontally to the ground on
a Roman Chair for at least two minutes or on a 45-degree bench for four minutes. If you can do that, then the strength of the lower back should be adequate. Check the glutes as well. Although I have no scientific proof, I’ve found most people with flat-back posture have inhibited glutes.
Cervical Spine: Slightly extended
Thoracic Spine: Upper part, increased flexion; lower part is straight Lumbar Spine: Straight,(flexed)
Pelvis: Tilted towards the back of the body. (Posterior tilt) Hip Joints: Extended
Knee Joints: Extended
Ankle Joints: Slightly tilted downwards (Plantar flexion) (13)
SWAY-BACK POSTURE (picture)
People tend to misuse this term. Most often people refer to this posture as Kyphosis-Lordosis posture. In fact, this condition has more in common with Flat-Back posture than the Kyphosis-Lordosis scenario.
Lordosis doesn’t really exist in the lumbar region. From the side, you’ll notice the forward position of the head, the increased curvature of the upper back (thoracic spine), the tail tucked under (posterior pelvic tilt) with the hip and knees hyper-extended. The key here is the hip and knee joints. This is what creates the sway.
Muscles short and facilitated: Hamstrings, upper fibers of the Internal Oblique. Neck Extensors
Elongated and Inhibited: One-joint hip-flexors, External Oblique, upper back extensors and neck flexors.(14)
When people are left or right handed a typical pattern seems to emerge. With right-handed people the right shoulder is lower than the left, the pelvis is slightly deviated toward the right while the right hip appears slightly higher than the left. There is usually a slight deviation of the spine toward the left and the left foot is more pronated (flat footed) than the right. These handedness patterns related to posture begin at an early age. The deviation in the hip towards the opposite side may appear as early as age 8 or 10. Usually shoulder correction tends to follow correction of the lateral pelvic tilt, but the reverse does not necessary occur.(15) Picture A is the right-handed version and picture B is the left-handed version.
Good and faulty posture of the feet and knees.
The feet should neither be flat-footed (pronated) or excessively arched (supinated). The knee caps or patellae face directly forward over the big and first toe. If the feet excessively pronate, the knees will rotate outward (laterally) and the tibias will rotate inward (medially). This is often seen in woman with postural knock-knees or (Genu Valgum). Excessive pronation can cause a host of problems, hallicus valgus (bunions), ACL problems, posterior tibialis tendonitis, plantar fascitis, achilles tendonitis, tarsal tunnel syndrome, medial shin splints, patella femoral syndrome and lower back pain.(16)
The opposite of knock-knees posture is bowlegs or Genu Varum. This is a combination of pronation of the feet medial rotation fo the femurs and hyper-extension of the knees. Not a lot of problems are seen in the clinical setting with this type of posture. It’s more common in men than women.
There are more factors that can contribute to these conditions which are beyond the scope of this article. Most often the condition is structural or neurological not muscular. In other words, a person has developed a faulty motor pattern which causes the problems. Sometimes one causes the other of vise- versa.
Ideal posture is a lot more important than you think. Postural dysfunction is most often muscular but can become structural if left unmanaged. During the first stages of faulty posture the ligamentous structural components (ligaments and joint capsules) are shortened or lengthened. However, if left unchecked for an extended period, a structural dysfunction will result, which can be far more difficult to correct. The first step for you or your client is awareness. Now, that you have the knowledge and information, you should be able to do something about it.
Good luck and don’t forget to STAND UP and SIT UP STRAIGHT.
- Purvis, Tom, RTS Manual, The Trunk, 2001 edition, p. 105
- Norkin, Cynthia, Levange, Pamela, Joint Stucture and Function, 2nd edition, p.421
- Kendall, F.P., McCreary, E.K., Provance, P.G., Muscles Testing and Function, 4th edition p.83
- Janda V. Too many to list.
- Lieberson, Craig, Rehabilitation of the Spine, 1996, p.26
- Chek, Paul, Core Conditioning Video Series
- Norkin, Cynthia, Levange, Pamela, Joint Stucture and Function, 2nd edition, p.84
- Lieberson, Craig, Rehabilitation of the Spine, 1996, p.27
- Janda V., Central nervous motor regulation and back problems; Neurobiologic Mechanisms in Manipulative Therapy, New York, Plenum, 1978
- Chek, Paul, Golf Conditioning Video Series
- Kendall, F.P., McCreary, E.K., Provance, P.G., Muscles Testing and Function, 4th edition p.84
- Kendall, F.P., McCreary, E.K., Provance, P.G., Muscles Testing and Function, 4th edition p.87
- Kendall, F.P., McCreary, E.K., Provance, P.G., Muscles Testing and Function, 4th edition